Synthesis of γ-MnO2/PANI Composites for Supercapacitor Application in Acidic Electrolyte

Abstract

In this paper, γ-MnO2 was prepared via simple hydrothermal method and chosen to compound γ-MnO2/polyaniline (PANI) composite electrode by in situ polymerization. The electrochemical performances of as-prepared samples were explored in acidic and neutral medium, respectively. And influenced its effects such as the different additions of composites, scan rates, and current densities in 0.5 M H2SO4 electrolyte were further investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), respectively. The good capactive behaviours indicated that the γ-MnO2 in the conductive matrix of PANI restrains them from dissolution in acidic electrolyte, and PANI itself affords an additional electrochemical activity to the composite. A asymmetric supercapacitor was fabricated using γ-MnO2/PANI as the positive electrode and activated carbon (AC) as the negative electrode. It displayed good capacitance performance of 232.1 F g−1 and high energy density 66.4 Wh kg−1 at a power density of 350.1 W Kg−1, as well as good cycling life (maintaining 78.65% initial capacitance after 3000 cycles). The enhanced electrochemical performances implie that the γ-MnO2/PANI composite can be potentially applied in superca-pacitors.